Researchers from the Perelman School of Medicine at the University of Pennsylvania (UPenn) studied more than 197,000 patients with psoriasis, 12,000 patients with psoriatic arthritis, 54,000 patients with rheumatoid arthritis (RA), and 1.2 million matched controls. Outcomes of interest were any liver disease, non-alcoholic fatty liver disease, and cirrhosis.

Patients with psoriatic skin or joint disease had a higher risk for serious liver disease, and patients with psoriasis taking a systemic therapy drug had the highest risk. Patients with RA taking similar drugs had the lowest liver disease risk.

The study also found that as the body surface area affected by psoriasis increased, so did the prevalence of liver disease and cirrhosis. In general, previous research has found that severity of psoriasis is linked to an increased risk of death. A study from UPenn researchers published in the same journal in August found that patients with psoriasis on 10% or more of their body had nearly double the risk of death.

The study adjusts for risk factors commonly seen in liver disease, such as alcohol use and diabetes.

“These findings offer evidence for the long-held view that psoriasis patients may be more predisposed to liver disease than patients with rheumatoid arthritis,” first author Alexis Ogdie, MD, MSCE, an assistant professor of Medicine and Epidemiology at the University of Pennsylvania, said in a statement. “Understanding the role of inflammation in liver disease and how the liver can perpetuate inflammation in these conditions can help us advise patients, and their clinicians, on how to more effectively manage their health.”

According to the authors, the findings suggest that systemic inflammation plays a significant role in liver disease development, but that medications used to treat these diseases can cause liver toxicity.

The authors suggest that future research look into whether control of inflammation reduces risk of liver disease.

“Based on these data, physicians should educate psoriasis patients on the increased risk for liver disease and be cautious about the use of hepatoxic medications in these patients, especially when additional risk factors such as diabetes, obesity, or heavy alcohol use are present,” said senior author Joel M. Gelfand, MD, MSCE, a professor of Dermatology and Epidemiology at UPenn.